JP3491899B2 - Motor rotation stop confirmation device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fail-safe motor rotation stop confirmation device capable of confirming a motor rotation stop by reliably distinguishing between a motor rotation state including rotation due to inertia and a stopped state. In particular, the present invention relates to the technology of a rotation sensor that extracts a detection output of rotation / stop of a motor.

[Background technology]

Conventionally, when using a motor-driven device, in order to ensure the safety of the worker, a safety device is required to detect and notify when the stopped motor suddenly starts when it is not intended. It is said that. As such a safety device, the applicant of the present invention can reliably detect that the rotation of the motor (including the rotation due to inertia) has stopped, and yet provide high safety with excellent fail-safety when the device breaks down. We are proposing a motor rotation stop confirmation device (PCT /
See JP93 / 00411).

  The operation of the rotation stop confirmation device will be described below.

This device is equipped with a bridge circuit with a transducer coil on one side for converting the rotation or stop state of the motor into an electric signal, and the detection output of the presence or absence of the motor rotation is an unbalanced output signal (AC signal) of the bridge circuit. Sensor unit (rotation sensor) that is generated by converting to changes in
A rotation presence / absence determination circuit that includes a fail-safe window comparator already known in the specification of tent 4,661,880 and the like, and uses a logical value output of the window comparator based on a detection output from the sensor unit as a determination output of the presence or absence of motor rotation. And is configured.

In the determination operation, when the motor is in the stopped state, the detection output from the sensor unit becomes constant. When this constant level detection output is input from the sensor unit to the rotation presence / absence determination circuit, a window comparator of the rotation presence / absence determination circuit generates an output signal having a logical value 1 indicating a motor stopped state (corresponding to a safe state). On the other hand, when the motor is in a rotating state (including rotation due to inertia), the detection output from the sensor section periodically fluctuates according to the rotation. When this periodically varying detection output is input from the sensor unit to the rotation presence / absence determination circuit, the window comparator of the rotation presence / absence determination circuit
Logical value 0 indicating the motor rotation state (corresponding to a dangerous state)
Output signal is generated. Further, when a failure occurs in the sensor unit, the rotation presence / absence determining circuit, or the like, the output of the window comparator becomes a logical value 0 indicating the dangerous side, and the configuration is fail-safe.

However, the rotation stop confirmation device of the prior art has the following problems because the bridge circuit is used in the sensor section.

One of the problems is that when the excitation winding of the motor is used as the transducer coil connected to one side of the bridge circuit, the impedance of the excitation winding differs depending on the motor used. When a pickup coil that detects the rotation of the motor is used as a transducer coil based on changes in the irregularities around the metal rotating body that is rotationally driven by the motor, the size of the pickup coil differs depending on the shape of the metal rotating body. Therefore, it is necessary to make an adjustment for appropriately setting the unbalanced output signal of the bridge circuit each time the detection target for detecting the presence or absence of rotation changes. In other words, the unbalanced output signal level when the motor is stopped is within the upper and lower threshold range (called window) of the window comparator, and the unbalanced output signal level becomes the window when the bridge circuit rotates or fails. It is necessary to adjust the unbalanced output signal level of the bridge circuit according to the detection target so as to be outside the range. This adjustment requires two adjustments: amplitude adjustment of the unbalanced output signal (adjustment of resistance value on one side of the bridge circuit) and phase adjustment (adjustment of capacitance of resonant capacitor).

Another problem is that there is a case where the output of the window comparator becomes a logical value 1 when multiple failures occur. That is, when a bridge circuit is used in the sensor unit, if a disconnection or a short circuit failure occurs in an element that constitutes one side of the bridge circuit, a high-level unbalanced output signal is generated. When such a single failure of the bridge circuit occurs, an upper threshold value is required for the window comparator to detect it. Moreover, since the unbalanced output of the bridge circuit at the normal time is a small level, an amplifier is required to amplify the unbalanced output, but this amplifier outputs the output within the upper and lower threshold ranges of the window comparator at the time of failure. It must not occur, and must have the characteristic that the amplified output decreases when a failure occurs. If the amplifier produces an output within the window comparator window upon failure, the window comparator cannot detect a single amplifier failure and is not failsafe.

Therefore, when multiple faults occur where the faults of the bridge circuit and the amplifier overlap, the output level from the amplifier falls within the upper and lower threshold range of the window comparator due to the canceling action of the high level output of the bridge circuit and the low level of the amplifier. In some cases, the window comparator may generate an output signal having a logical value of 1 indicating safety (stop of motor rotation) despite the breakdown of the device.

The present invention has been made in view of the above circumstances, and it is necessary to make a complicated adjustment even if a detection target is changed by using a configuration in which a bridge circuit is not used for a rotation sensor that generates a detection output of the presence or absence of rotation of a motor. In addition, even if an amplifier that amplifies the detection output of the rotation sensor is used, it is possible to provide a rotation stop confirmation device that can secure fail-safe property in the event of multiple failures in which failures of the rotation sensor and the amplifier occur at the same time. To aim.

[Disclosure of Invention]

Therefore, the motor rotation stop confirmation device according to the first aspect of the present invention includes a rotation sensor that generates an output signal according to the rotation / stop of the motor, and a logical value in the motor rotation stop state based on the output signal from the rotation sensor. 1 and a fail-safe rotation presence / absence determination circuit which generates a logic value 0 in a motor rotation state and also generates a logic value 0 in the event of a failure. A first rectifier circuit for rectifying by inputting an AC signal generated from a sensor according to rotation / stop of a motor; and a high-frequency signal generator for generating a high-frequency signal superimposed on an output signal of the first rectification rotation,
An amplifier that amplifies the output signal on which a high frequency signal is superimposed and saturates at the rotation sensor output signal level during motor rotation,
A capacitor for transmitting the output signal of the first rectifier circuit, which is interposed between the high-frequency signal generator and the amplifier and superposed with the high-frequency signal, to the amplifier, and second for rectifying the output of the amplifier. A first rectifying circuit, a first input terminal to which an output signal of the first rectifying circuit on which the high-frequency signal is superimposed are directly input, and a second input terminal to which a rectified output from the second rectifying circuit is input; A motor stop determination output having a logical value of 1 only when the levels of both signals input to the input terminal and the second input terminal are simultaneously within a predetermined threshold range determined by the upper limit value and the lower limit value preset for each input terminal. And a signal level input to the first input terminal is out of a threshold range when a sensor fails, and a signal level input to the second input terminal is a threshold range during motor rotation. A rotation stop confirmation device for a motor configured to set the respective threshold ranges of the first and second input terminals so that the rotation sensor has a high-frequency current signal in a winding of a tachogenerator incorporated in the motor. Is supplied, the high frequency current signal is modulated by the output signal of the tachogenerator, and the modulated signal is transmitted to the rotation presence / absence determination circuit as an output signal according to rotation / stop of the motor.

If the tacho generator built into the motor is used as in this configuration, the rotation detection output of the motor can be extracted without using the bridge circuit for the rotation sensor.
Then, even if the motor to be detected changes, it is not necessary to perform troublesome output adjustment of the rotation sensor. In addition, it is possible to generate a higher level detection output than a rotation sensor using a bridge circuit, an amplifier for amplifying the detection output of the rotation sensor is unnecessary, and the double rotation sensor and the amplifier simultaneously fail. It is no longer necessary to consider the problems caused by failures.

As a specific configuration of the rotation sensor, the scope of claim 2
As described in the item 1, an AC signal generator that generates a high-frequency AC signal, a first winding in which a secondary winding is connected in series with a winding of a tachogenerator, and a primary winding is connected to the AC signal generator.
A transformer and current-voltage conversion means for converting a current signal flowing in a series circuit of the secondary winding of the first transformer and a winding of the tachogenerator into a voltage signal and transmitting the voltage signal to the rotation presence / absence determining circuit. .

Here, the current-voltage converting means may be a resistance element that is inserted in series with the series circuit of the windings of the first transformer and the tachogenerator, and the series circuit of the windings of the first transformer and the tachogenerator may be used. The primary winding may be inserted in series, and the output signal of the secondary winding may be input to the rotation presence / absence determining circuit to form a second transformer. When the second transformer is used, at least one core of the first transformer and the second transformer is made of a saturable magnetic material.

In the configuration using the transformer, the threshold value of the window comparator of the rotation presence / absence determination circuit may be only the lower limit. In addition, the rotation sensor side and the rotation presence / absence determination circuit side including the electronic circuit can be insulated by the transformer.

Further, the rotation presence / absence determining circuit may be provided with a fail-safe on-delay circuit which delays the output of the 2-input window comparator by a predetermined delay time and outputs the delayed time when the failure occurs.

As a result, in the configuration using the transformer, the logical value 1 of the window comparator which is intermittently generated when the motor is rotating.
Output can be masked, and the reliability of the rotation presence / absence determination circuit can be improved.

A motor rotation stop confirmation device according to a second aspect of the invention is a motor rotation stop confirmation device including the rotation presence / absence determination circuit according to claim 1, wherein the rotation sensor detects a rotation of the motor. A coil whose inductance changes depending on the presence or absence, an oscillation circuit which includes a capacitor that forms a resonance circuit with the coil, and whose oscillation frequency changes according to the inductance change of the coil, and the frequency of the oscillation circuit is converted into a voltage for rotation. This is a configuration including a frequency-voltage conversion circuit that transmits the presence / absence determination circuit.

In this case, the rotation of the motor is converted into a frequency change and extracted, and this frequency is converted into a voltage. With such a configuration, when the motor to be detected is changed, it is only necessary to adjust the capacitor capacity of the oscillation circuit, and the number of adjustment elements is smaller than that of the rotation sensor using the bridge circuit, and the adjustment becomes easy. Further, it is not necessary to provide an amplifier for amplifying the output of the rotation sensor.

A motor rotation stop confirmation device according to a third aspect of the present invention includes a rotation sensor that generates an output signal according to the rotation / stop of the motor, and outputs a logical value 1 in a motor rotation stop state based on the output signal from the rotation sensor. And a fail-safe rotation presence / absence determination circuit that generates a logic 0 output in a motor rotation state and also generates a logic 0 output when a failure occurs, and the rotation presence / absence determination circuit generates from the rotation sensor. A first amplifier that amplifies an alternating current signal according to the rotation and stop of the motor, a first rectifier circuit that rectifies the amplified output of the first amplifier, and a high-frequency signal that is superimposed on the output signal of the first rectifier circuit High frequency signal generator, a second amplifier that amplifies the output signal on which the high frequency signal is superimposed and saturates at the output signal level of the rotation sensor during motor rotation, the high frequency signal generator and the second amplifier A capacitor for transmitting the output signal of the first rectifier circuit, which is interposed between the first rectifier circuit and the high frequency signal, to the second amplifier, and a second rectifier circuit for rectifying the output of the second amplifier. A first input terminal to which the output signal of the first rectifying circuit on which the high-frequency signal is superimposed is directly input, and a second input to which a rectified output from the second rectifying circuit is input
When the levels of both signals having an input terminal and input to the first input terminal and the second input terminal are simultaneously within a predetermined threshold range determined by an upper limit value and a lower limit value preset for each input terminal. Generates a motor stop judgment output of logical value 1 only 2
An input window comparator, wherein the signal level input to the first input terminal is outside the threshold range when the sensor fails, and the signal level input to the second input terminal is outside the threshold range when the motor is rotating. A rotation stop confirmation device for a motor configured to set each threshold range of two input terminals, wherein the rotation sensor includes a resonance circuit including a capacitor and a transducer coil whose inductance changes depending on whether or not the motor rotates. An AC signal generator that supplies an AC current signal to the resonance circuit, and a terminal voltage signal of the resonance circuit that changes with rotation of the motor is output as an output signal according to rotation / stop of the motor. This is a configuration for transmitting to the rotation presence / absence determination circuit.

According to such a configuration, even when a failure occurs in which the output level of the rotation sensor rises and an amplifier that amplifies the output of the rotation sensor also fails at the same time, the output increase degree of the rotation sensor is higher than that of the bridge circuit. Because of its small size, the output from the amplifier can be kept at a level lower than the lower threshold of the window comparator.

A specific configuration of the transducer coil is such that the transducer coil is housed and fixed in a coil housing case on a mounting member provided in the vicinity of a metallic rotating body that is rotationally driven by a motor, and is substantially the same around the metallic rotating body. The irregularities formed at intervals may be arranged facing each other with a predetermined interval.

Further, if at least one of the signal transmission elements other than the transducer coil that constitutes the rotation sensor is housed in a storage case different from the coil storage case and fixed to the mounting member, the transducer coil is always mounted. The rotation sensor does not operate normally unless it is fixed to the member. Therefore, it is possible to prevent a malicious mischief such as mounting the transducer coil in the vicinity of another metallic rotary body without mounting it in the vicinity of the metallic rotary body to be monitored.

If the transducer coil has a transformer structure including a primary coil and a secondary coil, it is possible to set only a lower limit threshold in the window comparator.

If a low-pass filter is provided between the rotation sensor and the rotation presence / absence determination circuit, a resonant circuit is formed in the transducer coil structure in which the primary coil and the secondary coil are loosely coupled and the reception level of the secondary coil is low. Even if a disconnection failure occurs in the capacitor that constitutes the secondary coil and the frequency selection characteristic of the secondary coil is lost, high-frequency noise can be removed and the reliability of the rotation stop confirmation device can be improved.

Further, a filter circuit for receiving the output signal of the second amplifier of the rotation presence / absence determination circuit and removing a high frequency signal component superimposed on the output signal, and a third rectifying circuit for rectifying the output from the filter circuit, When the energization signal to the motor is input to the input terminal and the rectified output of the third rectifier circuit is input to the other input terminal, the output of the logical value 1 is output when the input signal levels of both input terminals are both higher than a predetermined threshold value. A fail-safe first AND that outputs a logical value of 0 when a failure occurs
If a motor operation permission signal generation circuit that includes a gate and uses the output signal of the logical value 1 of the first AND gate as a permission signal for continuing the operation of the motor is provided, the transducer coil of the rotation sensor is far from the metal rotating body. When the rotation of the metallic rotating body cannot be monitored due to the distance, the rotation of the motor can be immediately stopped, and the safety of the worker can be secured.

Further, a filter circuit for receiving the output signal of the second amplifier of the rotation presence / absence determination circuit and removing a high frequency signal component superimposed on the output signal, and a third rectifying circuit for rectifying the output from the filter circuit, When the energization signal to the motor is input to the input terminal and the rectified output of the third rectifier circuit is input to the other input terminal, the output of the logical value 1 is output when the input signal levels of both input terminals are both higher than a predetermined threshold value. A fail-safe first AND that outputs a logical value of 0 when a failure occurs
The output signal of the first AND gate is input to the gate and one input terminal, and the output signal of the first rectifier circuit of the rotation presence / absence determination circuit is input to the other input terminal so that the input signal levels of both input terminals are both predetermined. It is composed of a fail-safe second AND gate that generates an output signal of logical value 1 when it is higher than a threshold value and outputs an output signal of logical value 0 when a failure occurs, and continues the operation of the motor with the output signal of logical value 1 of the second AND gate. By providing a motor operation permission signal generation circuit that is used as the permission signal of the motor rotation, the motor rotation can be performed not only when the transducer coil is far away from the metal rotating body but also when the transducer coil approaches the metal rotating body abnormally. It can be stopped immediately, and the safety of the worker can be further enhanced.

If an ON-delay circuit having a predetermined delay time is connected to the output side of the filter circuit and the output signal of the logical value 1 from the ON-delay circuit is used as the rotation decrease signal, for example, this rotation By connecting a light emitting diode etc. to the output of the decrease, it becomes possible to notify this by the light emitting diode when the motor rotation speed has decreased to a safe rotation speed even if an operator approaches, and it can be inspected in the rotation state of the motor etc. Is possible.

A motor rotation stop confirmation device according to a fourth aspect of the present invention includes a rotation sensor that generates an output signal according to the rotation / stop of the motor, and a logical value 1 in a motor rotation stop state based on the output signal from the rotation sensor. And a fail-safe rotation presence / absence determination circuit that generates a logic 0 output in a motor rotation state and also generates a logic 0 output in the event of a failure. A first rectifier circuit that rectifies by inputting an AC signal corresponding to the rotation / stop of the motor generated from the first rectifier circuit;
An amplifier that amplifies the output signal on which the high frequency signal is superimposed and saturates at the output signal level of the rotation sensor during motor rotation, and the high frequency signal is superimposed between the amplifier and the high frequency signal generator. A capacitor for transmitting the output signal of the first rectifier circuit to the amplifier, a second rectifier circuit for rectifying the output of the amplifier, and an output signal of the first rectifier circuit on which the high frequency signal is superimposed are directly input. A first input terminal and a second input terminal to which the rectified output from the second rectifier circuit is input, and the levels of both signals input to the first input terminal and the second input terminal are the same for each input terminal at the same time. A two-input window comparator that generates a motor stop judgment output having a logical value of 1 only when it is within a predetermined threshold range defined by the upper limit value and the lower limit value set in advance, and a signal input to the first input terminal is provided. Rotation of the motor having a configuration in which each threshold range of the first and second input terminals is set so that the level is outside the threshold range when the sensor fails and the signal level input to the second input terminal is outside the threshold range when the motor rotates. A stop confirmation device, a filter circuit for inputting an output signal of an amplifier of the rotation presence / absence determining circuit to remove a high frequency signal component superimposed on the output signal, and a third rectifying circuit for rectifying an output from the filter circuit And a logic value when the energization signal to the motor is input to one input terminal and the rectified output of the third rectifier circuit is input to the other input terminal and the input signal levels of both input terminals are both higher than a predetermined threshold value. 1 and a fail-safe first AND gate whose output becomes a logical value 0 when a failure occurs. An output signal of a logical value 1 of the first AND gate is output as a permission signal for continuing the operation of the motor. In this configuration, a motor operation permission signal generating circuit, which is referred to as a signal, is provided.

According to this, even in the case of mechanical equipment whose rotation rarely stops, when a sensor or the like fails, it is possible to immediately know the failure of the sensor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing a first embodiment of a motor rotation stop confirmation device according to the first present invention.

FIG. 2 is a circuit example of a 2-input window comparator.

  FIG. 3 is a circuit example of the rectifier circuit.

FIG. 4 is a time chart for explaining the operation of the first embodiment, where (a) is a sensor output signal waveform when the motor rotation is normal and when it is abnormal, and (b) is a sensor output signal when the motor is rotating. The waveform, (c), shows the output signal waveform of the first rectifying circuit of the rotation presence / absence determining circuit in the normal state.

  FIG. 5 is a circuit diagram of a second embodiment of the first invention.

FIG. 6 is a time chart showing the signal waveforms of the tacho generator, the transformer and the rectifier circuit for explaining the operation of the second embodiment.

  FIG. 7 is a circuit example of an on-delay circuit.

  FIG. 8 shows an example of a circuit that is not fail-safe.

FIG. 9 is a circuit diagram showing an embodiment of the motor rotation stop confirmation device according to the second invention.

FIG. 10 is a frequency-voltage characteristic diagram for explaining the operation of the above embodiment.

FIG. 11 is a circuit diagram of a first embodiment of the motor rotation stop confirmation device according to the third invention.

FIG. 12 is a view showing a coil mounting structure of the first embodiment.

FIG. 13 is a diagram showing the relationship between the distance between the metallic rotating body and the coil and the output of the first rectifying circuit.

FIG. 14 is a circuit example of the first amplifier of the rotation presence / absence determining circuit.

FIG. 15 is an input / output characteristic diagram of the amplifier of FIG. 14 when a single failure occurs.

  FIG. 16 is a modification of the first embodiment.

  FIG. 17 is a circuit diagram of the second embodiment.

FIG. 18 shows an example of the coil storage structure of the second embodiment,
(A) shows the case of the loose coupling structure, and (B) shows the case of the close engagement structure.

  FIG. 19 is a modification of the second embodiment.

  FIG. 20 is a circuit diagram of the third embodiment.

  FIG. 21 is a circuit diagram of essential parts of the fourth embodiment.

FIG. 22 is a diagram showing measurement data of attenuation characteristics of a sensor output with a change in distance between a transducer coil and a metallic rotating body.

FIG. 23 shows the structure of the rotation sensor used for the measurement of FIG. 22, (A) shows the circuit diagram of the rotation sensor, and (B) shows the coil housing structure.

FIG. 24 is a diagram showing a preferred example of the mounting structure of the transducer coil.

FIG. 25 is a view showing an unfavorable example of a transducer coil mounting structure.

FIG. 26 is a diagram showing a positional deviation state of the coil storage case.

  FIG. 27 is a circuit diagram of the fifth embodiment.

  FIG. 28 is a circuit diagram of essential parts of the sixth embodiment.

FIG. 29 is a time chart for explaining the operation of the circuit of FIG.

[Best Mode for Carrying Out the Invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing a first embodiment of a motor rotation stop confirmation device using a tachogenerator according to the first invention.

In FIG. 1, a motor M to be detected by this device
Rotatably drives the movable body _Rot via the gear head GH and the rotation axis Ax, and has a tacho-generator incorporated therein. A series circuit of the resistors R ₁ and R ₂ and the secondary winding N ₂ of the first transformer T is connected to the output terminals P ₁ and P ₂ of the tacho generator. The AC signal generator 1 is a transformer T 1
A high frequency AC signal is output to the secondary winding N ₁ , and this alternating output signal is supplied as a current signal to the output lines P ₁ and P ₂ of the tacho generator via the secondary winding N ₂ of the transformer T. Here, the rotation sensor of this embodiment is composed of an AC signal generator 1, a transformer T, resistors R ₁ and R _2, and a tacho generator.

The detection output of the rotation / stop of the motor of this rotation sensor is
A voltage signal is output from between the resistor R ₁ and the output terminal P ₁ and input to the sensor signal input terminal J of the motor rotation determination circuit PRC. Therefore, the resistor R ₁ has a function as a current-voltage converting means.

The rotation presence / absence determining circuit PRC is a signal processing circuit for processing the output signal of the rotation sensor to reliably determine whether the motor is in a rotating state (including rotation due to inertia) or in a stopped state.

The first rectifier circuit REC1 is for superposing the input signal from the rotation sensor on the power supply voltage V _CC of the rotation presence / absence determination circuit PRC, rectifying it, and performing envelope detection. The high frequency signal generator 2 is
The first rectifier circuit for generating a high frequency signal and passing through the resistor R ₃
The output signal of REC1 via the resistor R ₄ is superimposed. The broadband amplifier AMP is a first rectifier circuit REC1 on which a high frequency signal is superimposed.
Is for amplifying the output signal of the first rectifier circuit REC1 and is saturated at the output level of the first rectifier circuit REC1 when the motor is rotating. The capacitor C ₁ is for transmitting the output signal of the first rectifier circuit REC 1 on which the high frequency signal is superimposed to the wide band amplifier AMP. The second rectifier circuit REC2 is a wideband amplifier
It is for rectifying the output signal of AMP and performing envelope detection. Fail-safe 2-input window comparator 3
Is a fail-safe configuration in which an output of logical value 1 is not generated at the time of failure, the output signal of the first rectifier circuit REC1 in which the high frequency signal is superimposed is input to the first input terminal A, and the output signal to the second input terminal B is The second rectifier circuit R amplified by the broadband amplifier AMP
When the rectified signal rectified by EC2 is input and the levels of both signals are both within the upper and lower threshold range preset for each input terminal, the motor is judged to be in a stopped state and the output y of logical value 1 is output. It occurs. Such fail-safe window comparators are disclosed in USPatent 4,661,800, USPatent 5,027,114 and Japanese Patent Publication No. 1-2300.
PCT / JP9, which is already known in the publication No. 6, etc.
It has the same configuration as 3/00411.

Figure 2 shows the circuit configuration of a fail-safe window comparator. Since the circuit of FIG. 2 has a fail-safe AND function, it is a two-input fail-safe window comparator / AND gate to be precise.

In FIG. 2, R _{201 to} R ₂₁₈ are resistors, Q _{11 to} Q ₁₇ are transistors, A and B are input terminals, V _CC is a power supply potential of a window comparator, and 203 is a rectifier circuit. In the figure, the parts surrounded by the one-dot chain line are the transistors Q ₁₁ , Q ₁₂ , and Q ₁₃ and the transistors Q ₁₅ and Q.
Directly connected DC amplification circuits 201 and 202 using ₁₆ and Q ₁₇ are configured, and both have the same DC amplification circuit configuration. The difference from a general DC amplifier circuit is that the transistors Q ₁₁ and Q ₁₅ are outside the power supply potential V _CC (the emitters of the NPN transistors Q ₁₁ and Q ₁₅ are connected to the power supply potential V _CC ). is there. Therefore, the bases of the transistors Q ₁₁ and Q ₁₅ must be supplied with an input signal having a potential higher than the power supply potential V _CC . Also, the transistors Q ₁₁ and Q
₁₅ collectors are input terminals via resistors R _{201 and} R ₂₁₁ , respectively.
The input terminals A and B are connected to A and B, and the power supply voltage V _CC
It can be seen that the transistor Q ₁₁ and the transistor Q ₁₅ do not operate as an amplifier unless a higher level input signal (referred to as an input signal of the potential outside the power supply frame) is supplied. The transistor Q ₁₄ constitutes a phase inverting circuit (inverter) and has a function of inverting and amplifying the output signal of the DC amplifier circuit 201. Like the transistors Q ₁₁ and Q ₁₅ , the transistor Q ₁₄ also operates with a base input and a collector input (supplied from the input terminal A via the resistor R ₂₀₉ ) having a potential higher than the power supply potential V _CC . Base input signal of the transistor Q ₁₅ is so supplied from the collector of the transistor Q _14, signal transistor higher than the power supply potential V _CC Given high input level signal from the power supply potential V _CC is the input terminal A potential Q It will be supplied to ₁₅ bases.

Although the emitters of the transistors Q ₁₃ and Q ₁₇ are both at the ground potential, the collectors are connected to the input terminals A and B through the resistors R ₂₀₆ .R ₂₀₇ and R ₂₁₆ .R ₂₁₇ , respectively, so that the input terminal A
If an input signal having a potential higher than the power supply potential V _CC is supplied to B and B, the collector potentials of the transistors Q ₁₃ and Q ₁₇ are at the ground potential when turned on, and the potentials of the input terminals when turned off, that is, The potential is higher than the power supply potential V _CC . ON / OFF of this transistor Q ₁₃ and transistor Q ₁₇
The switch signal due to is transmitted through resistor R ₂₀₃ to the base of transistor Q ₁₄ and resistor R ₂₀₃ to the base of transistor Q _11.
Since it is supplied via ₂₁₃ respectively, transistor Q
₁₄ uses the output signal of the collector of the transistor Q ₁₈ ,
The transistor Q ₁₁ can be switched (NO / OFF) by using the output signal of the collector of the transistor Q ₁₇ .

That is, in the circuit of FIG. 2, the DC amplifier circuit 201 is directly connected to the DC amplifier circuit 202 via the transistor Q _14, and the output signal of the DC amplifier circuit 202 is directly connected to the DC amplifier circuit 201 via the resistor R _218. And constitutes a feedback oscillator.

The condition for the circuit of FIG. 2 to oscillate is that if the input potential of the input terminal A is V ₁₀ and the input potential of the input terminal B is V ₂₀ ,
It is determined by the following formula.

Regarding input terminal A, (r ₂₀₁ + r ₂₀₂ + r ₂₀₃ ) V _CC / r ₂₀₃ ≤V ₁₀ ≤ (r ₂₀₆ + r ₂₀₇ ) V _CC / r ₂₀₇ (1) Regarding input terminal B, (r ₂₁₁ + r ₂₁₂ + r ₂₁₃ ) V _CC / r ₂₁₃ ≤ V ₂₀ ≤ (r ₂₁₆ + r ₂₁₇ ) V _CC / r ₂₁₇ (2) In the above two equations, r _{201 to} r ₂₁₇ represent the resistance value of each resistor. In equation (1), (r ₂₀₁ + r ₂₀₂ + r ₂₀₃ ) V _CC / r ₂₀₃ represents the lower threshold of input terminal A, and (r ₂₀₆ + r ₂₀₇ ) V _CC / r ₂₀₇ represents the upper threshold of input terminal A. Represent Similarly, in equation (2),
(R ₂₁₁ + r ₂₁₂ + r ₂₁₃ ) V _CC / r ₂₁₃ represents the lower threshold of the input terminal B, and (r ₂₁₆ + r ₂₁₇ ) V _CC / r ₂₁₇ represents the upper threshold of the input terminal B. When the input terminal A has an input level V ₁₀ in the range satisfying the expression (1) and the input terminal B has an input level V ₂₀ in the range satisfying the expression (2), the circuit of FIG. 2 oscillates. An AC output signal is generated at the terminal Uf, and this AC output signal is rectified by the rectifier circuit 203 to become a DC output signal (when an AC output signal is not generated at the terminal Uf, a DC voltage higher than the power supply potential V _CC Output signal is not generated).

In addition, the circuit of FIG. 2 can generate an AC output signal by oscillating only when a DC input voltage satisfying the expressions (1) and (2) is supplied to the input terminals A and B, respectively. Has a gate function. Moreover, since both the input terminals A and B have the function of the window comparator, they are called 2-input window comparator / AND gate.

The circuit of FIG. 2 has a characteristic that it cannot oscillate when a short circuit or a disconnection failure occurs in a transistor and a resistor that form the circuit, and even if a circuit element fails, both the input terminals A and B In addition, it has a characteristic that it cannot oscillate unless the input voltage defined by the equations (1) and (2) is supplied. For this reason, the circuit of FIG. 2 is called a fail-safe window comparator / AND gate.

As shown in FIG. 3, the rectifier circuits REC1 and REC2 are
It consists of one capacitor C ₂ and C ₃ and two diodes D ₁ and D ₂ . The capacitor C ₂ is a coupling capacitor for transmitting the AC signal of the rotation sensor, the capacitor C ₃ is a smoothing capacitor for smoothing only the high frequency component of the output signal of the rectifying diode D ₁ , and in this embodiment, Although a 4-terminal capacitor is used, a normal 2-terminal capacitor may be used. The diode D ₂ is a clamping diode for superimposing the signal transmitted by the capacitor C ₂ on the power supply voltage V _CC , and the diode D ₁ is for rectifying the signal superimposed on the power supply potential V _CC . It is a rectifying diode.
The rectifier circuit 203 of the window comparator 3 has the same structure.

Here, the coupling capacitor C ₂ in the first rectifier circuit REC 1 is electrostatic so that not only the high frequency signal of the AC signal generator 1 but also the low frequency output signal of the tacho-generator accompanying the rotation of the motor M can be transmitted. The capacity is increased. On the other hand, the smoothing capacitor C ₃ has a capacitance that smoothes only the high frequency signal of the AC signal generator 1 and cannot smooth the low frequency signal of the tacho generator. Therefore, the capacitor
The terminal voltage of C ₈ , that is, the rectified output of the rectifier circuit REC1, when the motor M is stopped and there is no output signal of the tacho generator, becomes a constant level output obtained by rectifying the high frequency signal from the AC signal generator 1, When the motor M rotates and an output signal is generated in the tacho generator, it changes with the amplitude of the low frequency signal.

Next, the operation of the motor rotation stop confirmation device of the first embodiment shown in FIG. 1 will be described.

The detection output from the rotation sensor is the rotation presence / absence determination circuit PRC.
Is input to the rectifier circuit REC1 and rectified. In this rectified signal,
The signal on which the high frequency signal from the high frequency signal generator 2 is superimposed is input to the first input terminal A of the window comparator 3 and also to the wide band amplifier AMP via the capacitor C ₁ . The signal on which the high-frequency signal input to the wideband amplifier AMP is superimposed is amplified by the wideband amplifier AMP and the rectifier circuit R
The second of the window comparator 3 after envelope detection by EC2
Input to the input terminal B.

First, when the rotor of the motor M is stopped, no output signal is generated from the tacho generator. At this time, as shown by the solid line in (a) of FIG. 4, the signal divided by the resistors R ₁ and R ₂ of the high frequency signal supplied from the AC signal generator 1 to the transformer T is the rotation presence / absence determining circuit. PRC rectifier circuit REC1
To enter. The rectified output level of the rectifying circuit REC1 case, a constant level of the signal S1 shown in the FIG. 4 by the smoothing action of the capacitor C ₂ (c). A signal obtained by superimposing a high frequency signal on the signal S1 having a constant level is input to the first input terminal A of the window comparator 3. The upper threshold ThAH and the lower threshold ThAL of the first input terminal A of the window comparator 3 are set as shown in (c) of FIG. 4, and the input signal at this time is within the upper and lower threshold ranges. , The oscillation condition of the window comparator 3 is satisfied. When the rectified output of the rectifier circuit REC1 is at a constant level, the rectified output of the rectifier circuit REC2 is within the upper and lower thresholds of the second input terminal of the window comparator 3. Therefore, when the motor M is in the stopped state, the output of the logical value 1 is generated from the window comparator 3, which indicates that the motor is in the stopped state.

On the other hand, when the rotor of the motor M is rotating, the tacho generator produces an output signal. This output signal is a low-frequency AC signal corresponding to the rotation of the rotor. At this time, as shown in FIG. 4B, the high frequency signal from the AC signal generator 1 is input to the rectification circuit REC1 of the rotation presence / absence determination circuit PRC as a modulation signal modulated by the output signal of the tacho generator. Rectified output of the rectifier circuit REC1 at this time, since only the high-frequency signal is smoothed by the capacitor C ₃ for smoothing, the signal S1 'which changes periodically as shown in the FIG. 3 (c). In this case, the signal input to the first input terminal A of the window comparator 3 is within the range of the upper and lower threshold values, and the oscillation condition is satisfied. However, in the wideband amplifier AMP, this change is amplified and saturated,
The high frequency input signal is masked during this saturation period and is generated intermittently in the linear region of the wide band amplifier AMP.
The high-frequency signal that appears intermittently is rectified by the rectifier circuit REC2 and input to the second input terminal B of the window comparator 3, but the signal level becomes lower than the lower limit threshold ThAL of the second input terminal B. Therefore, the window comparator 3 does not satisfy the oscillation condition of the second input terminal B, the output of the window comparator 3 becomes a logical value 0, and the motor M is in the rotating state.

In the circuit shown in FIG. ₁ , when a disconnection failure occurs in the windings N ₁ and N ₂ of the transformer T or a disconnection failure occurs in the resistor R ₁ , the motor M
4 is in a stopped state, the high frequency signal from the AC signal generator 1 shown in FIG. 4 (a) is not input to the rectifying circuit REC1 of the rotation presence / absence determining circuit PRC. If the resistor R ₂ has a disconnection fault, the tacho generator terminals P ₁ and P ₂ are disconnected, or the tacho generator winding has a disconnection fault, the tacho generator output signal is transmitted to the rectifier circuit REC 1. However, at this time, the output signal of the transformer T is directly transmitted to the capacitor C ₂ of the rectifier circuit REC ₁ through the resistor R ₁ . But,
Since this signal is not a signal divided by the resistors R ₁ and R ₂ , it has a high level indicated by the dotted line in FIG. 4 (a), and the rectified output level of the rectifier circuit REC 1 is the same as that of the window comparator 3. It becomes higher than the upper limit threshold ThAH of one input terminal, the output of the window comparator 3 becomes a logical value 0, and the output form is the same as when the motor M is in the rotating state. Therefore, the configuration is fail-safe.

As described above, if the rotation sensor for extracting the detection output of the rotation / stop of the motor M is configured to use the output signal of the tachogenerator, it is possible to operate like a bridge circuit even when the motor to be detected changes. No need for troublesome adjustments. Further, since the output level from the rotation sensor can be increased, an amplifier for amplifying the sensor output can be eliminated, and there is no problem when multiple failures occur in which the rotation sensor and the amplifier simultaneously fail. .

Next, a fifth embodiment using the tachogenerator is described as a fifth embodiment.
Shown in the figure and described. The same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 5, in this embodiment, the AC signal generator ₁ is connected to the primary winding N ₁ of the first transformer T via the resistor R. To the output terminals P ₁ and P ₂ of the tacho generator, a series circuit of a current reducing resistor R ′, a secondary winding N ₂ of the first transformer T and a primary winding N ₁₁ of the second transformer T1 is connected. . The secondary winding N ₁₂ of the transformer T1 is connected to the rectifier circuit REC1 of the rotation presence / absence determination circuit PRC ′. Here, in this embodiment, the second transformer T1 has a function of current-voltage converting means. Then, at least one of the two transformers T and T1 is configured by a transformer using a saturable magnetic material core (transformer having nonlinearity). In the rectifier circuit REC1 of this embodiment, the capacitance of the coupling capacitor C ₂ and the smoothing capacitor C _2, not greater need to vary, as in the first embodiment, the high-frequency signal generator 1 frequency Any configuration that can rectify a signal may be used.

Next, the operation of the second embodiment shown in FIG. 5 will be described.

When the rotor of the motor M is stopped and there is no output signal of the tacho generator, the output signal of the AC signal generator 1 passes through the transformer T and the coil of the tacho generator and the primary winding of the transformer T1 via the resistor R '. It is input to N ₁₁ , and this output signal is transmitted to the secondary winding N ₁₂ side.

On the other hand, when the rotor of the motor M is rotating and an output signal is being generated in the tachogenerator, by configuring both transformers T, T1 or one of them with a transformer using a saturable magnetic core, saturable The AC signal generator 1 in which the transformer side using the magnetic core is saturated by the output current of the tachogenerator and is transmitted to the secondary winding N ₁₂ side of the transformer T1.
Output signal level decreases. In this way, in this embodiment, the AC signal of the AC signal generator 1 is modulated by the output signal of the tacho generator. FIG. 6 shows the output current i of the tacho generator and the second transformer in this embodiment.
Secondary output e of T1, and shows the relationship between the rectified output e ₃ 'of the rectifier circuit REC1.

That is, when the motor M is no output current i of the tachogenerator is stopped, the output signal e of the transformer T1, a high level, the first input terminal A of the rectified output e ₃ 'is the window comparator 3 of the rectifying circuit REC1 Exceeds the lower threshold ThAL of. At this time, the rectified output of the rectifier circuit REC2 input to the second input terminal B of the window comparator 3 also becomes a value exceeding the lower threshold of the second input terminal B, and the logical value indicating the stopped state of the motor M from the window comparator 3 An output of 1 is generated.

On the other hand, when the output current i of the tachogenerator is generated while the motor M is rotating, the output signal e ₃ of the transformer T1 becomes low level because the transformer using the saturable magnetic core is saturated, and the rectifier circuit REC1 Rectified output e ₃ 'is lower than the lower limit threshold of the first input terminal A of the window comparator 3, and the rectified output of the rectifier circuit REC2 is also the window comparator 3
Is lower than the lower limit threshold value of the second input terminal B. However, in this case, since the output current i of the tacho generator is an alternating current, there are periodically points (zero points) at which the current i becomes zero,
Output signal e _{3 of} transformer T1 and rectified output of rectifier circuit REC1
As shown in FIG. 6, e ₃ 'is periodically set to a high level, the input level of the window comparator 3 periodically exceeds the lower limit threshold, and the motor is stopped by the window comparator 3 even though the motor M is rotating. The output of the logical value 1 that indicates is generated intermittently.

Therefore, in the rotation presence / absence determination circuit PRC ′ of the second embodiment,
As shown in FIG. 5, after the window comparator 3,
As shown in PCT / JP93 / 00411 filed earlier, a fail-safe on-delay circuit 4 is provided to generate an output only when the output signal of the window comparator 3 continues for a predetermined time. The output is used as the determination output of the rotation presence / absence determination circuit PRC ′. As a result, the output signal of the logic value 1 of the window comparator 3 generated intermittently is masked, and when the motor M is in the rotating state, the rotation presence / absence determination circuit PRC ′ continuously outputs the determination output of the logic value 0. , It can be shown that the motor M is in a rotating state. The fail-safe on-delay circuit has a characteristic that the delay time initially set is not shortened due to a circuit failure. Further, in the second embodiment, the window comparator 3 need only have the lower limit threshold value (the upper limit threshold value of the window comparator 3 is set to a sufficiently high level and the window comparator is used as a level detector).

FIG. 7 shows an example of an on-delay circuit having a fail-safe function with a simple structure.

In FIG. 7, assuming that the input resistance of the window comparator 90 is sufficiently higher than that of the resistor R ₃₁ , the input signal y = 1 (the input signal having a level higher than the power supply potential V _CC ) from the window comparator 3 is input. After that, the oscillation delay of the window comparator, that is, the delay time is determined by the threshold value of the resistor R ₉₁ , the four-terminal capacitor C ₉₁ and the window comparator 90. The circuit of FIG. 7 can make the output signal zero even if the resistor R ₉₁ has a disconnection fault or the electrode of the capacitor C ₉₁ has a disconnection or short-circuit fault.

In the case of the second embodiment as well, similar to the first embodiment, even if the motor for detecting the rotation is changed, the troublesome adjustment on the rotation sensor side is unnecessary. In addition, the second embodiment is characterized in that the output line of the tacho generator and the electronic circuit such as the rotation presence / absence determination circuit PRC ′ can be insulated by the second transformer T1.

In the second embodiment, the secondary winding N ₂ of the second transformer T and the output terminals P ₁ and P ₂ of the tacho generator are connected in series so that the output signal of the AC signal generator 1 is the output terminal P _{1 of the} tacho generator. it is important that the structure is supplied as a current signal to P _2. This allows the output terminal of the tacho generator
When P ₁ and P ₂ are disconnected, or when the winding of the tachogenerator is broken, the output signal of the AC signal generator 1 is not transmitted to the rotation presence / absence determination circuit PRC ′ side, and the output of the rectifier circuit REC1. The signal e _g ′ becomes zero, and the rotation presence / absence determination circuit PRC ′ outputs the logical value 0, which is the same as when the motor M is rotating, which is fail safe. That is, in the first aspect of the invention, the AC current signal of the AC signal generator 1 serves as an inspection signal for inspecting the tachogenerator failure detection.

By the way, it is also possible to adopt the circuit configuration shown in FIG. That is, the third winding N ₃ is provided on the first transformer T,
The secondary winding N ₃ is connected to the output terminals P ₁ and P ₂ of the tacho generator via a current reducing resistor R ′. The transformer T is a transformer using a saturable magnetic core.

In this case, when there is no output current i of the tachogenerator, the transformer T is not saturated, and the output signal of the AC signal generator 1 passes from the primary winding N ₁ to 2 of the transformer T via the current reducing resistor R.
Rotation presence / absence determination circuit PR transmitted to the secondary winding N ₂ in a high level state
An output signal of logical 1 indicating that the motor M is stopped is generated from C '. When the output current i is generated from the tacho generator, the transformer T is saturated by this output current i, so that the AC signal generator transmitted from the primary winding N ₁ to the secondary winding N ₂ of the transformer T is generated. The output signal of 1 becomes low level, and the output signal of logical value 0 indicating the rotation of the motor M is generated from the rotation presence / absence determination circuit PRC ′.

Such a configuration has an advantage that only one transformer is required as compared with the circuit shown in FIG. However, if the output terminals P ₁ and P ₂ of the tacho generator are disconnected, or if the current reduction resistor R ′ or the tacho generator has a disconnection failure, the transformer T is not saturated and the output signal from the AC signal generator 1 is Primary winding N ₁
Is transmitted to the secondary winding N ₂ in a high level state, and although the motor M is rotating, the rotation presence / absence determination circuit PRC ′ generates an output signal of a logical value 1 indicating that the motor M is stopped. However, there is a drawback that fail-safety cannot be ensured. This is because the output current of the AC signal generator 1 is not directly supplied to the winding of the tacho generator and is not used as a test signal for detecting the failure of the tacho generator (the tacho generator has a voltage signal). Is supplied).

Next, FIG. 9 shows an embodiment of the second invention. The same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

This is a configuration in which a rotation sensor that generates a detection output of the presence or absence of rotation of the motor M converts an inductance change of a pickup coil as a transducer coil that converts the rotation of the motor into an electric signal into a frequency change of an oscillator and extracts the frequency change. .

In FIG. 9, the pickup coil L is a motor M.
It detects irregularities around the metallic rotating body (not shown) driven by the, and is installed in the vicinity of the metallic rotating body. When the metallic rotating body is rotated by the motor M, the distance between the pickup coil L and the metallic rotating body is periodically changed due to passage of irregularities around the rotating body, and the rotation of the motor M is changed due to the inductance change of the pickup coil L. Can be detected. The excitation winding of the motor is a simple coil when the motor power switch is OFF, so the excitation winding of the motor may be used instead of the pickup coil.

The oscillator 10 is constructed by incorporating a pickup coil L, and in the present embodiment, a transistor Q ₁ and a resistor R.
_A well-known transistor amplifier is constituted by _{11 to} R ₁₄ , and the capacitors C ₁₁ and C ₁₂ (determining the oscillation frequency) and the pickup coil L are used as a resonance circuit to form a Colpitts oscillator. The resistors R ₁₁ and R ₁₂ are emitter resistors, and the resistors R ₁₃ and R ₁₄ are bias resistors. The capacitor C ₁₅ is the secondary winding N ₂ of the transformer T.
This is a DC blocking capacitor for preventing a DC current from flowing from the collector of the transistor Q ₁ to the base via the.

The oscillation frequency f of the oscillator 10 is roughly determined by the following equation (3), where the capacitances of the capacitors C ₁₁ and C ₁₂ are C ₁₁ and C _12, and the inductance of the pickup coil L is L.

f = 1 / 2π (LC ₀ ) ^1/2 (3) However, C ₀ = C ₁₁ · C ₁₂ / (C ₁₁ + C ₁₂ ). Also,
If the numbers of turns of the primary winding N ₁ and the secondary winding N ₂ of the transformer T are made equal, the inductance of the pickup coil L seen from the secondary side of the transformer T is approximately L.

The transistor Q ₂ and the resistor R _{13 form} an emitter follower amplifier, and perform impedance matching with the LC filter of the frequency-voltage converter 20 in the next stage. Capacitor C ₂₁ and inductor L ₂₁ are high-pass L equivalent to the LC filter.
The C-filter is composed and the frequency-voltage conversion circuit 20
Outputs a voltage signal according to the output frequency from the oscillator 10 to the rotation presence / absence determining circuit PRC.

That is, the rotation sensor of FIG. 9 is configured to extract a change in the inductance of the pickup coil L as a change in the frequency of the oscillator 10 and convert this change in frequency into a change in voltage.

  Next, the operation will be described.

When the motor M is in a rotating state, the uneven portion around the metal rotating body periodically faces the pickup coil L as the metal rotating body rotates. For example, the recess is the pickup coil L
When the oscillating frequency of the oscillator 10 corresponding to the inductance of the coil L when it is faced with is set to f ₁ and the output signal of the frequency-voltage conversion circuit 20 at this time is set to e ₁ , a convex part is generated as the motor M rotates. When facing the pickup coil L, the distance between the coil and the metallic rotating body is reduced and the inductance of the pickup coil L is reduced, so that as shown in FIG.
The oscillation frequency of the oscillator 10 increases by Δf, and the output signal e _g from the frequency-voltage conversion circuit 20 also increases by Δe _s from e ₁ to e ₂ . Thus, the motor M be in a rotating state, the input signal of the rotation existence determination circuit PRC periodically changes with an amplitude of .DELTA.e _s between e ₁ -e _2. In this case, the input signal level on the second input terminal B side of the window comparator 3 in the rotation presence / absence determination circuit PRC becomes lower than the lower limit threshold, so that the output signal of the rotation presence / absence determination circuit PRC becomes a logical value 0.

On the other hand, when the motor M is in the stopped state, the input signal of the rotation presence / absence determination circuit PRC becomes a signal of a constant level between e _{1 and} e ₂ depending on the stop position of the metallic rotating body. By setting this signal level within the threshold range of the window comparator 3, the output signal of the window comparator 3 becomes the logical value 1 when the motor M is stopped.

According to the configuration of this embodiment, when it is necessary to change the pickup coil L due to the change of the metallic rotating body, it is only necessary to adjust the capacitances of the resonance capacitors C ₁₁ and C ₁₂ of the oscillator 10. It is easier to adjust than a sensor circuit using a conventional bridge circuit. Further, if the output level of the oscillator 10 is increased by increasing the power supply V _CC , the amplifier for amplifying the output of the rotation sensor is unnecessary.

Next, the motor rotation stop confirmation device of the third invention will be described.

FIG. 11 shows a circuit diagram of the first embodiment of the third invention.
The same elements as those in FIG. 1 are designated by the same reference numerals and their description is omitted.

In FIG. 11, the rotation sensor of this embodiment is a metal rotating body R ₀₁ that rotates integrally with the AC signal generator 1 and the motor M.
Pickup coil L as a transducer coil for detecting the rotation of the coil, a capacitor C _S1 connected in parallel with the pickup coil L to form a resonance circuit, and a resistor R
It is composed of _a1 and R ₃₂ . A series resonance circuit in which the pickup coil L and the capacitor C _S1 are connected in series may be used. Further, in the case of the rotation presence / absence determination circuit PRC "of the present embodiment, which inputs the detection output from the rotation sensor and determines whether or not the metal rotating body R ₀₁ is rotating, in the preceding stage of the rectifying circuit REC1,
A fail-safe first amplifier AMP1 for amplifying an input signal from the rotation sensor is provided, and other configurations are similar to those shown in FIG. In the present embodiment, the amplifier AMP corresponds to the second amplifier.

  The mounting structure of the rotation sensor is shown in FIG.

In FIG. 12, a pickup coil L is housed in a coil housing case 30 and fixed to the upper surface of a mounting bracket 31 which is arranged in the vicinity of a metallic rotating body R ₀₁ having irregularities around it. The resistors C ₃₁ , C ₃₂ and the capacitor C _{31 which} are the signal transmission elements of the rotation sensor other than the pickup coil L are housed in the accessory storage case CS different from the coil storage case 30 and fixed to the upper surface of the mounting bracket 31. There is. Coil storage case 30 side pickup coil L and accessory storage case CS
The component on the side is connected via a lead wire (indicated by a dotted line in FIG. 12). The accessory storage case CS has terminals X ₁ and X ₂
Connected to the AC signal generator 1 side through a connection with rotating existence determination circuit PRC "side through the terminal X _3. Note that the AC signal generator 1 is installed at a different remote location from the rotation sensor The rotation presence / absence determination circuit PRC "side is provided. Then, the coil storage case 30, the accessory storage case CS and the mounting bracket
31 comprises a transducer head part.

  Next, the operation of the circuit shown in FIG. 11 will be described.

The current supplied from the AC signal generator 1 is supplied to the resonance circuit of the pickup coil L and the capacitor C ₃₁ via the resistor R ₃₁ , and the terminal voltage of the resonance circuit is supplied to the rotation presence / absence determination circuit PRC via the resistor R _32. ", Where the convex and concave portions around the metallic rotating body _Rot and the pickup coil L
If the distance between and is W ₁ , W ₂ (W ₁ <W ₂ ),
With the rotation of the metal rotor R _ot , the distance between the metal rotor R _a1 and the pickup coil L changes periodically, and the terminal voltage of the resonance circuit changes according to the change in the inductance of the pickup coil L. The input signal level to the presence / absence determination circuit PRC "changes.

Fig. 13 shows the relationship between the distance change between the metallic rotor _Rot and the pickup coil L and the rectified output of the rectifier circuit REC1 of the rotation presence / absence determination circuit PRC ", where f _r is the AC signal generator 1
Is the oscillation frequency of. The rectified outputs are e ₁ and e ₂ (e ₁ <e ₁ <when the convex part and the concave part of the metallic rotating body R _ot are close to each other.
e ₂ ). The rectified output e ₃ is when there is no metallic rotating body (W = ∞).

Therefore, when the metallic rotating body _Rot is rotated by the motor M, the output level of the rectification circuit REC1 of the rotation presence / absence determination circuit PRC "changes periodically, so that the second input terminal B side of the window comparator 3 The input level of does not satisfy the oscillation condition, and the output of the window comparator 3 becomes a logical value 0. On the other hand, when the metallic rotor _Rot is stopped, the rectified output is between e _{1 and} e ₂ . Since the level is constant and the upper and lower thresholds of the first and second input terminals of the window comparator 3 are set as shown in FIG. 13, the output of the window comparator 3 becomes the logical value 1 and the metal rotation Body R _ot
Indicates that is stopped.

Further, by setting the upper limit threshold ThAH of the first input terminal A of the window comparator 3 between the rectified outputs e ₂ and e ₃ , the rotation presence / absence determination circuit when the pickup coil L comes off the mounting bracket 31 and falls off. It is possible to generate a logical 0 output indicating danger from PRC ".

Further, when the disconnection failure occurs in the pickup coil L and the capacitor C ₃₁ , the output level of the terminal X ₃ , that is, the input level of the amplifier AMP1 of the rotation presence / absence determination circuit PRC ″ increases. At this time, the amplified output of the amplifier AMP1 decreases. Even if such failures occur at the same time, according to the rotation sensor of the present embodiment, the increase in output is smaller than that of the conventional bridge circuit, so that the input level of the window comparator 3 can be kept within the threshold value of the window comparator 3. Therefore, fail-safe property can be secured.

  This will be described below.

FIG. 14 shows a configuration example of the fail-safe amplifier AMP1, and FIG. 15 shows an example of input / output characteristics when the amplifier AMP1 has a single failure.

In FIG. 15, the horizontal axis represents the input signal e _a (peak-to-peak of the amplifier AMP1.
-Peak value), and the vertical axis is the output signal e (rectified output of the rectifier circuit REC1 when the output signal of the transformer T ₄₁ and the input signal of the rectifying circuit REC1). The curve a if the amplifier AMP1 is in a normal operating condition, the other curve a ₁ ~a _4, etc. are shown the input and output characteristics when the amplifier AMP1 has failed. In the figure, for example, Q
₄₂ : Short circuit between CB (in the case of curve a ₂ ) means a short circuit between the collector and the base of the transistor Q ₄₂ as shown in FIG. 14, and i _CB = i ₁ + i ₂ + i _{3 is added} to the transistor Q _42. Means that it is always flowing. A short circuit between Q _{41 and} CE (in the case of curve a ₃ ) means a short circuit between the collector and the base of the transistor Q ₄₁ . FIG. 15 also shows the amplifier of FIG.
Failures such as disconnection between input and output due to failure of AMP1 (eg disconnection failure of base of transistor Q ₄₁ or transistor Q ₄₂ , disconnection failure of transformer T ₄₁ or collector of transistor Q ₄₂ , etc.) are not shown. . The reason is that it is clear that the output signal e is not output (e = 0) in such a failure.

It can be seen from FIG. 15 that the amplifier AMP1 in FIG. 14 is reduced to a gain of 1/10 or less due to a failure. Therefore, even if a disconnection failure occurs in the pickup coil L and the capacitor C ₃₁ and further a failure occurs in the fail-safe amplifier AMP1, the output signal e of the rectifier circuit REC1 outputs the first output signal of the window comparator 3.
It is possible to set the level lower than the lower limit threshold of the input terminal A, and it becomes possible to secure sufficient fail-safe property against multiple failures.

Further, in this embodiment, the pickup coil L and the other accessories such as the resistors R ₃₁ and R ₃₂ and the capacitor C ₃₁ are divided into separate storage cases. The reason for this is that by fixing the accessory storage case CS to the mounting bracket 31 that is integrally fixed to the motor-driven device side and is arranged near the metal rotor R _ot , the pickup coil L must be the metal rotor R. _{This is} to prevent the rotation sensor from operating normally unless it is installed at a predetermined position near _ot . still,
The parts to be stored in the accessory storage case CS are resistors R ₃₁ , R ₃₂ ,
Any one of the capacitors C ₃₁ may be used. In addition, as shown in FIG. 16, the resistor R ₃₁ is housed on the side of the AC signal generator 1 installed at a place distant from the metallic rotating body _Rot, and its terminal is
X ₁ and the capacitor C ₃₁ is the pickup coil L
It may be configured such that it is housed in the coil storage case 30 together with, and only the resistor R ₃₂ is stored in the accessory storage case CS, and the terminal X ₄ for connecting the coil storage case 30 and the accessory storage case CS is provided. .

By doing so, if the coil storage case 30 is directly connected to the rotation presence / absence determination circuit PRC ", the output of the rotation presence / absence determination circuit PRC" (the output of the window comparator 3) cannot be set to the logical value 1. Become. For example, the 16th
When the coil storage case 30 shown in the figure is directly connected to the rotation presence / absence determination circuit PRC "via the terminal X ₄ and not through the accessory storage case CS, the signal attenuation effect due to the resistance R ₃₂ in the accessory storage case CS Output signal e of rectifier circuit REC1
Is higher than normal and exceeds the upper limit threshold ThAH of the first input terminal A of the window comparator 3.

That is, at least the pickup coil L should not be mounted on the mounting bracket 31 arranged near the metallic rotating body _Rot .
By connecting another pickup coil to the rotation presence / absence determination circuit PRC ", it is possible to prevent a malicious mischief such as placing the pickup coil near the metal rotary body _Rot equivalent and constantly generating a rotation stop signal. As shown in Fig. 16, not only resistance R ₃₂ but also resistance R inside the accessory storage case CS can be used to prevent mischief.
_31, who complicates the circuit configuration of the accessory accommodating case CS putting a capacitor C ₃₁ is effective. In particular, when the capacitor C ₃₁ is put in the accessory storage case CS, it is difficult to obtain a predetermined resonance circuit even if a coil different from the pickup coil L already installed is brought. That is, if the accessory storage case CS is integrated with the mounting bracket 31, the rotation presence / absence determining circuit PRC "unless the predetermined pickup coil L is mounted on the mounting bracket 31.
Can be a system that does not work.

  A second embodiment is shown in FIG.

In FIG. 17, the pickup coil L is composed of _two coils L ₁ and L ₂ which are coupled to each other. In this case, as the storing method of the coil housing case 30, the case of loose coupling apart Figure 18 (A) slightly coils L ₁ and L ₂ as the coil L ₁ as shown in FIG. (B) A method of overlapping and L ₂ to form a tight coupling is conceivable. In either case, the coupling between the coils changes due to the passage of the concavo-convex portion of the metallic rotating body _Rot that is brought close to the upper surface of the coil storage case 30.

According to the configuration of FIG. 17, when the coil L ₁ , L ₂ or the capacitor C ₃₁ has a disconnection fault, the output signal of the terminal X ₃ always drops, which is the case in the first embodiment shown in FIG. Moreover, the output signal of the rectifier circuit REC1 does not rise. Therefore,
Always consider the rectification circuit unless you consider a malicious mischief such as connecting another pickup coil to the rotation presence / absence determination circuit PRC ".
Since the output signal of REC1 drops at the time of failure, the first input terminal A of the window comparator 3 only needs to set the lower limit threshold ThAL. In addition, fail-safe performance can be secured even when the amplifiers AMP1 fail simultaneously.

However, as shown in FIG. 19, as in FIG.
R ₃₁ is stored in the AC signal generator 1 side and its output terminal is X ₁
And the capacitor C _{31 is connected} to the pickup coils L ₁ and L ₂
When the coil storage case 30 and the resistor R ₃₂ are stored together with the accessory storage case CS, the coil storage case 30 side is connected to the rotation presence / absence determination circuit PRC "via the resistor R _32. Normal connection state and coil storage case
To distinguish between not normal connection state of connecting directly to rotary existence determination circuit PRC "side 30 side without through the resistor R ₃₂ (if there is no attenuation of the output by resistance R _32), a first window comparator 3 The input terminal A requires the upper limit threshold ThAH.

Further, in FIG. 17, when the coupling system as shown in FIG. 18 (A) is adopted and the reception level of the coil L ₂ is low,
As shown in the figure, it is necessary to insert a low-pass filter LPF between the resistor R ₃₂ and the rotation presence / absence determination circuit PRC ″. That is, when a disconnection failure occurs in the capacitor C _{31 of the} resonance circuit,
Although the output level of the coil L ₂ decreases, on the other hand, the frequency selection characteristic of the coil L ₂ is lost, and it becomes easy to receive noise having a frequency higher than the output frequency of the AC signal generator 1. To eliminate this high frequency noise level, a low pass filter LP
F is required. The four-terminal capacitor is used
4 in order to prevent generation of the output signal from the rectifying circuit REC1 when event disconnection fault in the four terminals K ₁ ~K ₄ terminal capacitor occurs.

  Next, FIG. 20 shows a third embodiment.

In FIG. 20, the motor M is rotationally driven by connecting the DC power supply DC by turning ON the switch SW ₁ . The rotation presence / absence determination circuit PRC "that receives the detection output from the rotation sensor 40 that detects the rotation / stop of the motor M and determines the presence / absence of rotation is
It has the same configuration as shown in FIG. In addition, the rotation sensor 40
The pickup coil serving as the transducer coil may be configured with one coil as shown in FIG. 11 or may be configured with two coils as shown in FIG.

The first AND gate 50 has two input terminals a and b, and a switch SW ₂ interlocking with the switch SW ₁ is provided on the input terminal a side.
DC power supply (for AC power supply, switch SW ₂ and A
The voltage may be stepped down by a transformer and a rectifier circuit may be inserted) between the input terminal a of the ND gate 50). The rectified output of the rectifier circuit REC3 described later is input to the input terminal b.
The first AND gate 50 has a fail-safe structure and generates an output of logical value 1 when an input signal having a level higher than a preset threshold is input to the two input terminals a and b. The safe AND gate can be constructed by using the window comparator shown in FIG. 2 and setting the upper limit thresholds of the two input terminals to sufficiently high levels. As such a fail-safe AND gate that uses a window comparator, USPatent 4,
No. 661,880, etc.

The third rectifier circuit REC3 has two capacitors C ₅₁ , C ₅₂ and 2
It consists of two diodes D ₅₁ and D _52, and is connected to the amplifier A in the rotation presence / absence determination circuit PRC "via the resistor R ₆₀ and the 4-terminal capacitor C _60.
MP amplified output is input. The capacitor C ₆₀ constitutes a filter circuit for filtering the output component of the high frequency signal generator 2 in the rotation presence / absence determination circuit PRC ", and the resistor R ₆₀ is a capacitor presence / absence determination circuit in the capacitor C _60.
It is inserted so as not to affect the rectification circuit REC2 in the PRC ".

  Next, the operation will be described.

When the switch SW ₁ is turned on and the motor M is rotating,
The detection output from the rotation sensor 40 periodically changes according to the unevenness of the metal rotating body _Rot and is input to the rotation presence / absence determination circuit PRC ". Since the amplifier AMP amplifies and outputs this change, rectification is performed. The rectified output of the circuit REC3 becomes higher than the threshold value of the input terminal b of the first AND gate 50. The input terminal a of the first AND gate 50.
Switch SW ₂ turns ON in synchronization with the ON operation of switch SW _1.
Therefore, the input signal of a level higher than the threshold value of the input terminal a is input, and the output signal of the first AND gate 50 becomes the logical value 1 by the input of the output signal from the rectifier circuit REC3. Then, for example, the output signal of the logical value 1 of the first AND gate 50 can be displayed as a permission signal for continuing the operation of the motor M. On the other hand, when the switch SW ₁ is OFF and the motor M is stopped, the output signal of the first AND gate 50 has a logical value of 0, and the operation continuation permission signal disappears and the operation can be immediately stopped. Here, the first AND gate 50 and the rectifier circuit REC3
A motor operation permission signal generation circuit is configured including the capacitor C ₆₀ and the capacitor C ₆₀ . This motor operation permission signal generating circuit corresponds to the fourth invention.

According to such a configuration, when in the state in which the pickup coil L in the rotation sensor 40 is not in proximity to the metallic rotator R _ot, can not monitor the rotation of the metal rotation body R _ot is
No signal of a level higher than the threshold value of the input terminal b of the first AND gate 50 is generated from the rectifier circuit REC3, the output signal of the first AND gate 50 becomes a logical value 0, and the permission signal for continuing the operation of the motor M disappears. M can be stopped.

Therefore, when the pickup coil L falls off from the fitting 31 and a failure occurs in which the rotation of the motor M cannot be detected, the motor M can be immediately stopped.

By the way, in industrial equipment, a machine that constantly rotates is often used. When detecting the presence / absence of rotation of such a rotating machine, the output of the logical value 0 indicating the rotation state continues. On the other hand, if the rotation sensor etc. fails, the rotation presence / absence determination circuit is provided because of the fail-safe configuration.
The output of PRC "becomes zero. Therefore, even if a failure occurs in the pickup coil L or the like while the movable part is rotating, it will not be known until the movable part is stopped.

According to the apparatus of the present embodiment, when the pickup coil L fails, the rotation continuation permission signal from the AND gate 50 disappears, so that it is possible to immediately know when a failure occurs.

In FIG. 20, the energization signal of the motor M is input to the input terminal a of the AND gate 50 via the switch SW ₂ , but as shown in the fourth embodiment of FIG. The output of the current transformer CT is rectified by the rectifier circuit REC4.
It may be configured to be rectified by and input to the input terminal a of the first AND gate 50.

FIG. 22 is a secondary diagram when the distance W between the iron material (S10C) and the coil surface is changed by using the rotation sensor having the circuit configuration and the coil housing structure shown in FIGS. 23 (A) and (B). It shows the measurement result of the attenuation characteristic of the side output voltage.

The output voltages e ₁ , e ₂ , and e ₃ in Fig. 13 are 2 mm (=
It can be seen from FIG. 22 that the setting of the upper threshold ThAH of the window comparator 3 is a very delicate adjustment when corresponding to W ₁ ), 5 mm (= W ₂ ), and no iron material (W = ∞).

FIG. 24 shows an effective mounting structure for the coil storage case 30.

In FIG. 24, a printed circuit board is attached to a fitting 31 provided integrally with the motor drive unit in the vicinity of the metallic rotating body.
31A is fixed with a plurality of screws 31a. This printed circuit board 31A
A synthetic resin coil storage case 30 in which a pickup coil L is molded is fixed by a mounting screw 30a. The pickup coil L is connected to the wiring of the printed circuit board 31A via a mounting screw portion, and the accessory storage case C
It is electrically connected to the circuit elements inside S.

According to this mounting structure, the coil storage case 30
When the coil storage case 30 is tilted by a lateral force acting on the coil storage case 30, the force due to the tilt of the coil storage case 30 directly acts on the printed circuit board 31A via the mounting screw 30a to cause distortion.
When the wiring (for example, copper foil) of the printed circuit board 31A is broken or the coil storage case 30 is largely displaced, the coil storage case 30 falls off from the printed circuit board 31A.

On the other hand, in FIG. 25, the coil housing case 30 is fixed not to the printed circuit board 31A but to the mounting member 31, and the lead wire of the pickup coil is connected to the printed circuit board 31A.

In this structure, since the coil storage case 30 is fixed to the mounting fitting 31, it is stronger than the mounting structure shown in FIG. However, when a lateral force acts on the coil storage case 30 and the coil storage case 30 tilts as shown in FIG. 26, the force is received by the mounting bracket 31 side, so that the printed circuit board 31A and the lead wires are not affected. Printed circuit board with almost no effect
Breakage of 31A wiring or lead wire is unlikely to occur.

Therefore, if the mounting structure as shown in FIG. 24 is adopted in which the pickup coil is easily broken when an external force is applied to the coil storage case 30, an external force is applied to the coil storage case 30 and the coil storage case 30 is displaced from the normal position. If you do not consider malicious mischief, you only need to set the lower threshold, as the coil will be disconnected and the output will decrease when
It is possible to eliminate the need to set the upper threshold value that requires fine adjustment.

In reality, when an external force is applied to the coil storage case 30 mounted close to the metal rotary body, the coil storage case 30 is lifted up, that is, the pickup coil approaches the metal rotary body and the distance W is reduced. Is displaced to.
In this case, since the output signal changes due to the passage of the uneven portion of the metallic rotating body, the rotation of the motor can always be detected unless the rotation sensor has a failure. However, even if the rotation of the motor can be detected, it is not a normal state that the pickup coil approaches the metallic rotating body. For this reason, for example, when the distance between the pickup coil and the convex portion of the metallic rotating body is set to 2 mm, the lower limit threshold value is set to the output signal level corresponding to W = 1 mm, and operation is continued when the distance is further exceeded. A signal for prohibiting continuation may be generated.

However, this is not necessary if the coil storage case is electrically disconnected when lifted.

  Next, FIG. 27 shows a fifth embodiment.

In the figure, in this embodiment, in addition to the configuration of FIG.
A second AND gate 51 for inputting the output signal of the first AND gate 50 and the output signal of the rectification circuit REC1 in the rotation presence / absence determination circuit PRC "is provided, and the output signal of the logical value 1 of the second AND gate 51 is used as the permission signal for continuing the operation. Therefore, in the present embodiment, the first
In addition to the 1AND gate 50, the rectifier circuit REC3, and the capacitor C ₆₀ , the second AND gate 51 is included to form a motor operation permission signal generation circuit.

The second AND gate 51 may set a lower limit threshold value for the input level of the input terminal c and set an upper limit threshold value to a sufficiently high level. Regarding the input level of the input terminal d, a lower limit threshold may be set so that the output of the rectifier circuit REC1 when the rotation sensor 40 is closer than the predetermined distance W is out of the threshold range.

In this embodiment, the rotation sensor 40 is monitored for both dropout and abnormal approach. That is, when the rotation sensor 40 falls off, the output change of the rotation sensor 40 due to the rotation of the motor M does not occur, and the input signal level of the input terminal b of the first AND gate 50 decreases, so that the first AND gate 50 Becomes a logical value 0, the output signal of the second AND gate 51 becomes a logical value 0, and the operation continuation permission signal is stopped. In addition, the rotation sensor 40
Output of the second AND gate 51 when the pickup coil of the second AND gate 51 falls below a threshold value when the pickup coil of the second AND gate 51 approaches a metal rotating body that rotates together with the motor M by a predetermined distance or less. The signal becomes a logical value 0, and the operation continuation permission signal stops.

Then, as in the case of the circuit of FIG. 20, when the pickup coil L fails, the permission signal for continuing rotation from the AND gate 50 disappears, so even when applied to mechanical equipment in which the rotating portion rarely stops. The effect is that when a failure occurs, it is possible to immediately know the failure.

When the upper limit threshold value is set on the input terminal d side of the second AND gate 51 and the pickup coil is connected to the amplifier AMP1 without passing through the accessory storage case CS of FIG. 19, the input terminal d increases due to the rise of the output signal level. If the output signal of the AND gate 51 becomes a logical value 0 when the input signal level of the above exceeds the upper limit threshold value, it becomes possible to monitor whether or not the rotation sensor 40 is normally connected, and the coil storage case It becomes possible to monitor erroneous circuit connections in addition to dropouts and abnormal approaches.

In each of the embodiments shown in FIGS. 20 and 27,
The circuit shown in FIG. 28 may be added.

That is, in FIG. 28, the second circuit of the rotation presence / absence determination circuit PRC "is shown.
The capacitor C that filters the output of the amplifier AMP
Coupling capacitor on the output side of the filter circuit consisting of ₆₀
The on-delay circuit 52 is connected via C ₇₁ , and the light emitting diode LED is connected to the output side of the on-delay circuit 52. Diode D ₅₂ is a clamping diode that clamps the output of capacitor C ₅₂ to power supply potential V _CC .

According to this configuration, as shown in the time chart of FIG. 29, the frequency of the output of the capacitor C ₁ in the rotation presence / absence determination circuit REC ″ changes according to the decrease in the rotation speed of the motor M,
Thus, (the output signal of the capacitor C ₆₀₎ the input signal of the capacitor C ₅₁ in the amplifier AMP and the third rectifier circuit REC3 also changes. That is, when the rotation of the motor M decreases, the pulse width t ₁ of the input signal of the capacitor C ₅₁ in accordance with this, t ₂ ··· t _N
Becomes longer. When the pulse width becomes longer than the preset delay time T _ON of the on-delay circuit 52, the on-delay circuit 52 generates an output signal of logical value 1 and the light emitting diode LED lights up. Therefore, when the rotation speed of the motor M becomes lower than a predetermined speed (determined by the delay time of the on-delay circuit 52), the light emitting diode LED can be blinked.

According to such a configuration, the blinking of the light emitting diode LED makes it possible to know that the motor M has decreased to a safe rotation speed even when approached by an operator, and the device inspection and the like can be performed while the motor M is rotating. It becomes possible to do.

Regarding the motor operation permission signal generating circuit shown in FIGS. 20 and 27 or the circuit shown in FIG. 28 added to this circuit, the rotation sensor using the tacho generator shown in FIGS. 1 and 5 is used. It is needless to say that the present invention can be applied to the case where it is used or the case where the rotation sensor using the oscillator shown in FIG. 9 is used. Further, it is also applicable to the previously applied one using a rotation sensor using a bridge circuit (PCT / JP93 / 00411).

As described above, according to the first aspect of the invention, since the rotation signal of the motor is extracted by using the output signal of the tachogenerator, it is not necessary to adjust the rotation sensor even if the motor to be detected changes. it can. According to the second invention, the transducer coil is incorporated in a part of the oscillator to convert the rotation of the motor into a change in the oscillation frequency to extract the rotation signal of the motor. Therefore, the motor to be detected is changed. However, only the phase adjustment on the oscillator side can eliminate the need for adjustment on the rotation sensor side. In the first and second aspects of the invention, since the output level of the rotation sensor can be increased, it is not necessary to provide an amplifier that amplifies the output signal of the rotation sensor, and the simultaneous failure of the rotation sensor and the amplifier (multiplexing) Even if a failure occurs, the fail-safe property can be secured.

According to the third aspect of the invention, since the terminal voltage change of the resonance circuit of the transducer coil and the capacitor is extracted as the rotation signal of the motor, the rotation sensor does not need to be adjusted even if the motor to be detected changes. it can. Further, even when an amplifier for amplifying the output signal of the rotation sensor is provided, the output increase level at the time of failure of the rotation sensor can be suppressed to a small level, so that fail-safe property at the time of simultaneous failure with the amplifier can be secured.

Therefore, compared with the conventional technology that extracts the rotation signal of the motor using the unbalanced output signal of the bridge circuit, the circuit configuration is simple and the maintenance of the device is easy. Can be provided.

[Industrial availability]

INDUSTRIAL APPLICABILITY The present invention makes it easy to handle and secure a high level of safety when driving a load with a motor in industrial equipment that requires a high degree of safety, and is highly industrially applicable. is there.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Hobara 1-13-8 Kamikizaki, Urawa-shi, Saitama Nihon Signal Co., Ltd., Yono Works (56) Reference JP-A-1-185181 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01P 13/00

Claims (16)

(57) [Claims] 1. A rotation sensor for generating an output signal according to rotation / stop of a motor, and an output of a logical value 1 in a motor rotation stopped state based on an output signal from the rotation sensor,
A fail-safe rotation presence / absence determining circuit that generates a logical value 0 in the motor rotation state and generates a logical value 0 in the event of a failure is provided, and the rotation presence / absence determining circuit causes the rotation of the motor generated from the rotation sensor. A first rectifier circuit that inputs and rectifies an alternating current signal according to the stoppage, a high-frequency signal generator that generates a high-frequency signal that is superimposed on the output signal of the first rectifier circuit, and the output signal on which the high-frequency signal is superimposed An output signal of the first rectifier circuit, which is interposed between the high-frequency signal generator and the amplifier and which has a high-frequency signal superimposed thereon, A capacitor for transmitting to the amplifier,
A second rectifier circuit that rectifies the output of the amplifier, a first input terminal that directly receives the output signal of the first rectifier circuit on which the high-frequency signal is superimposed, and a second rectifier output that receives the rectified output from the second rectifier circuit. An input terminal, the first input terminal and the second
Two inputs that generate a motor stop judgment output having a logical value of 1 only when the levels of both signals input to the input terminals are simultaneously within a predetermined threshold range defined by the upper limit value and the lower limit value preset for each input terminal. A first comparator and a second comparator so that the signal level input to the first input terminal is outside the threshold range when the sensor fails and the signal level input to the second input terminal is outside the threshold range when the motor is rotating.
A rotation stop confirmation device for a motor configured to set each threshold range of an input terminal, wherein the rotation sensor supplies a high frequency current signal to a winding of a tacho generator incorporated in the motor, and the high frequency current signal Is modulated by the output signal of the tachogenerator, and the modulated signal is transmitted to the rotation presence / absence determination circuit as an output signal according to the rotation / stop of the motor. 2. The rotation sensor comprises an AC signal generator for generating a high frequency AC signal, a secondary winding connected in series with a winding of a tachogenerator, and a primary winding connected to the AC signal generator. A first transformer; and a current-voltage converting means for converting a current signal flowing in a series circuit of the secondary winding of the first transformer and a winding of the tachogenerator into a voltage signal and transmitting the voltage signal to the rotation presence / absence determining circuit. The rotation stop confirmation device for a motor according to claim 1, which is configured. 3. The motor rotation stop confirmation device according to claim 2, wherein the current-voltage conversion means is a resistance element inserted in series in a series circuit of a winding of the first transformer and a winding of the tachogenerator. 4. The current-voltage converting means, wherein a primary winding is inserted in series in a series circuit of windings of a first transformer and a tachogenerator, and an output signal of the secondary winding is input to a rotation presence / absence determining circuit. 3. The motor rotation stop confirmation device according to claim 2, wherein the rotation stop confirmation device for a motor according to claim 2, characterized in that the core of at least one of the first transformer and the second transformer is formed of a saturable magnetic material. 5. A fail-safe on-delay circuit for delaying the output of a 2-input window comparator by a predetermined delay time and providing a fail-safe on-delay circuit to the side that shortens the delay time when a failure occurs in the rotation presence / absence determining circuit. 5. The motor rotation stop confirmation device according to claim 4, characterized in that. 6. A rotation sensor for generating an output signal according to rotation / stop of a motor, and an output of a logical value 1 in a motor rotation stop state based on an output signal from the rotation sensor,
A fail-safe rotation presence / absence determining circuit that generates a logical value 0 in the motor rotation state and generates a logical value 0 in the event of a failure is provided, and the rotation presence / absence determining circuit causes the rotation of the motor generated from the rotation sensor. A first rectifier circuit that inputs and rectifies an alternating current signal according to the stoppage, a high-frequency signal generator that generates a high-frequency signal that is superimposed on the output signal of the first rectifier circuit, and the output signal on which the high-frequency signal is superimposed An output signal of the first rectifier circuit, which is interposed between the high-frequency signal generator and the amplifier and which has a high-frequency signal superimposed thereon, A capacitor for transmitting to the amplifier,
A second rectifier circuit that rectifies the output of the amplifier, a first input terminal that directly receives the output signal of the first rectifier circuit on which the high-frequency signal is superimposed, and a second rectifier output that receives the rectified output from the second rectifier circuit. An input terminal, the first input terminal and the second
Two inputs that generate a motor stop judgment output having a logical value of 1 only when the levels of both signals input to the input terminals are simultaneously within a predetermined threshold range defined by the upper limit value and the lower limit value preset for each input terminal. A first comparator and a second comparator so that the signal level input to the first input terminal is outside the threshold range when the sensor fails and the signal level input to the second input terminal is outside the threshold range when the motor is rotating.
A rotation stop confirmation device for a motor configured to set each threshold value range of an input terminal, wherein the rotation sensor forms a coil whose inductance changes depending on whether or not the motor rotates and a resonance circuit with the coil. A configuration including an oscillating circuit including a capacitor, the oscillating frequency of which changes in accordance with a change in the inductance of the coil, and a frequency-voltage converting circuit for converting the frequency of the oscillating circuit into a voltage and transmitting the voltage to the rotation presence / absence determining circuit. A motor rotation stop confirmation device characterized by: 7. A rotation sensor for generating an output signal according to rotation / stop of a motor, and an output of a logical value 1 in a motor rotation stopped state based on an output signal from the rotation sensor,
A fail-safe rotation presence / absence determining circuit that generates a logical value 0 in the motor rotation state and generates a logical value 0 in the event of a failure is provided, and the rotation presence / absence determining circuit causes the rotation of the motor generated from the rotation sensor. First amplifier that amplifies the alternating current signal according to the stoppage, first rectifier circuit that rectifies the amplified output of the first amplifier, and high-frequency signal generation that generates a high-frequency signal that is superimposed on the output signal of the first rectifier circuit And a second amplifier that amplifies the output signal on which the high frequency signal is superimposed and is saturated at the output signal level of the rotation sensor during motor rotation, and is interposed between the high frequency signal generator and the second amplifier. A capacitor for transmitting the output signal of the first rectifier circuit on which the high-frequency signal is superimposed to the second amplifier, and a second rectifier circuit that rectifies the output of the second amplifier,
A first input terminal to which an output signal of the first rectifier circuit on which the high-frequency signal is superimposed is directly input, and a second input terminal to which a rectified output from the second rectifier circuit is input, A motor stop determination output having a logical value of 1 is generated only when the levels of both signals input to the two input terminals are simultaneously within a predetermined threshold range defined by the upper limit value and the lower limit value preset for each of the input terminals. An input window comparator, wherein the signal level input to the first input terminal is outside the threshold range when the sensor fails, and the signal level input to the second input terminal is outside the threshold range when the motor is rotating.
And a rotation stop confirmation device for a motor configured to set respective threshold ranges of the second input terminal, wherein the rotation sensor comprises a capacitor and a transducer coil whose inductance changes depending on whether or not the motor rotates. Circuit and an AC signal generator that supplies an AC current signal to the resonance circuit, and outputs a terminal voltage signal of the resonance circuit, which changes with rotation of the motor, according to rotation / stop of the motor. A rotation stop confirmation device for a motor, characterized in that it is transmitted to the rotation presence / absence determination circuit as the above. 8. The transducer coil is housed and fixed in a coil housing case by a mounting member provided in the vicinity of a metallic rotating body that is rotationally driven by a motor, and is substantially equal around the metallic rotating body. 8. The motor rotation stop confirmation device according to claim 7, wherein the irregularities formed at intervals are arranged facing each other with a predetermined interval. 9. A structure in which at least one of the signal transmission elements other than the transducer coil constituting the rotation sensor is housed in a housing case different from the coil housing case and fixed to the mounting member. The motor rotation stop confirmation device according to item 8. 10. The transducer coil comprises a primary coil for transmitting an AC current signal supplied from the AC signal generator, and a secondary coil for receiving a transmission signal from the primary coil. A device for confirming rotation stop of the motor according to claim 8. 11. The motor rotation stop confirmation device according to claim 10, wherein a low-pass filter is provided between the rotation sensor and the rotation presence / absence determination circuit. 12. A filter circuit for inputting an output signal of a second amplifier of the rotation presence / absence determining circuit to remove a high frequency signal component superimposed on the output signal, and a third rectifying circuit for rectifying an output from the filter circuit. And when the energization signal to the motor is input to one input terminal and the rectified output of the third rectifier circuit is input to the other input terminal and the input signal levels of both input terminals are both higher than a predetermined threshold value, a logical value 1 And a fail-safe first AND gate whose output becomes a logical value of 0 when a failure occurs, and a motor operation permission signal which uses an output signal of a logical value of 1 of the first AND gate as a permission signal for continuing the operation of the motor. 8. The motor rotation stop confirmation device according to claim 7, further comprising a generation circuit. 13. An on-delay circuit having a predetermined delay time is connected to the output side of the filter circuit, and the on-delay circuit is connected.
13. The motor rotation stop confirmation device according to claim 12, wherein the output signal of logical value 1 from the delay circuit is used as a rotation reduction signal. 14. A filter circuit for inputting an output signal of a second amplifier of the rotation presence / absence determining circuit to remove a high frequency signal component superimposed on the output signal, and a third rectifying circuit for rectifying an output from the filter circuit. And when the energization signal to the motor is input to one input terminal and the rectified output of the third rectifier circuit is input to the other input terminal and the input signal levels of both input terminals are both higher than a predetermined threshold value, a logical value 1 And a fail-safe first AND gate whose output becomes a logical value 0 at the time of a failure, and the output signal of the first AND gate is input to one input terminal and the rotation existence determination circuit is input to the other input terminal. When the output signal of the rectifier circuit is input and both input signal levels of both input terminals are higher than a predetermined threshold value, an output signal of logical value 1 is generated, and at the time of failure, the output signal becomes logical value 0. Consists of a 2AND gate, said 2AND
8. The rotation stop confirmation device for a motor according to claim 7, further comprising a motor operation permission signal generation circuit that uses the output signal of the logic value 1 of the gate as a permission signal for continuing the operation of the motor. 15. An on-delay circuit having a predetermined delay time is connected to the output side of the filter circuit, and the on-delay circuit is connected.
15. The motor rotation stop confirmation device according to claim 14, wherein the output signal of logical value 1 from the delay circuit is used as a rotation reduction signal. 16. A rotation sensor for generating an output signal according to rotation / stop of a motor, and an output of a logical value 1 in a rotation stopped state of the motor based on an output signal from the rotation sensor. A fail-safe rotation presence / absence determining circuit that generates an output of a logical value 0 and also generates an output of a logical value 0 at the time of failure, and the rotation presence / absence determining circuit is provided.
A first rectifier circuit for inputting and rectifying an AC signal generated from a rotation sensor according to the rotation / stop of the motor; a high-frequency signal generator for generating a high-frequency signal superimposed on an output signal of the first rectifier circuit; An amplifier that amplifies the output signal on which the signal is superimposed and is saturated at the output signal level of the rotation sensor during motor rotation, and the high frequency signal that is interposed between the high frequency signal generator and the amplifier. A capacitor for transmitting the output signal of the first rectifier circuit to the amplifier, a second rectifier circuit for rectifying the output of the amplifier, and a direct input of the output signal of the first rectifier circuit on which the high frequency signal is superimposed 1 input terminal and a second input terminal to which the rectified output from the second rectifier circuit is input, and the levels of both signals input to the first input terminal and the second input terminal are at the same time for each of the input terminals. A two-input window comparator that generates a motor stop determination output having a logical value of 1 only when it is within a predetermined threshold range defined by the upper and lower limits set for the sensor, and the signal level input to the first input terminal is a sensor. When a failure occurs, the voltage is out of the threshold range, and the signal level input to the second input terminal is outside the threshold range when the motor is rotating.
And a rotation stop confirmation device for a motor configured to set each threshold value range of the second input terminal, wherein an output signal of the amplifier of the rotation presence / absence determination circuit is input and a high frequency signal component superimposed on the output signal is output. A filter circuit to be removed, a third rectifier circuit that rectifies an output from the filter circuit, an energization signal to the motor is input to one input terminal, and a rectified output of the third rectifier circuit is input to the other input terminal. When the input signal levels of both input terminals are both higher than a predetermined threshold value, an output of logical value 1 is generated, and a fail-safe first AND gate whose output becomes logical value 0 at the time of failure is formed. A motor rotation stop confirmation device comprising a motor operation permission signal generation circuit that uses an output signal of value 1 as a permission signal for continuing motor operation.